Begin at the intersection of the 110 freeway at approximately Avenue 55, move southwest along the 110 freeway to the intersection of the 110 freeway and Pasadena Avenue, south on Pasadena Avenue, southern boundary of Heritage Square Avenue 35, east to Griffin Avenue to Idylwild Avenue, north along Avenue 33 to Lupin Terrace, east to Von Keithian Street and the imaginary line to the summit of Flat Top of Hill, center of radio tower, to the corner of Sierra Street and Mercury Avenue, along due north imaginary line bisecting Debs Park, to 110 freeway.